[PATCH net-next v17 02/14] net: netdev netlink api to bind dma-buf to a net device

Mina Almasry
2024-07-30T02:26:34Z

API takes the dma-buf fd as input, and binds it to the netdevice. The
user can specify the rx queues to bind the dma-buf to.

Suggested-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>

---

v16:
- Use subset-of: queue queue-id instead of queue-dmabuf (Jakub).
- Rename attribute 'bind-dmabuf' to more generic 'dmabuf' (Jakub).
- Use 'dmabuf' everywhere instead of mix of 'dma-buf' and 'dmabuf'
(Donald).
- Remove repetitive 'dmabuf' naming that appeared in some places
(Jakub).
- Reordered where the new operations went so I don't break the enum UAPI
(Jakub).

v7:
- Use flags: [ admin-perm ] instead of a CAP_NET_ADMIN check.

Changes in v1:
- Add rx-queue-type to distingish rx from tx (Jakub)
- Return dma-buf ID from netlink API (David, Stan)

Changes in RFC-v3:
- Support binding multiple rx rx-queues

---
Documentation/netlink/specs/netdev.yaml | 47 +++++++++++++++++++++++++
include/uapi/linux/netdev.h | 11 ++++++
net/core/netdev-genl-gen.c | 19 ++++++++++
net/core/netdev-genl-gen.h | 2 ++
net/core/netdev-genl.c | 6 ++++
tools/include/uapi/linux/netdev.h | 11 ++++++
6 files changed, 96 insertions(+)

diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
index 959755be4d7f9..4930e8142aa63 100644
--- a/Documentation/netlink/specs/netdev.yaml
+++ b/Documentation/netlink/specs/netdev.yaml
@@ -457,6 +457,39 @@ attribute-sets:
Number of times driver re-started accepting send
requests to this queue from the stack.
type: uint
+ -
+ name: queue-id
+ subset-of: queue
+ attributes:
+ -
+ name: id
+ -
+ name: type
+ -
+ name: dmabuf
+ attributes:
+ -
+ name: ifindex
+ doc: netdev ifindex to bind the dmabuf to.
+ type: u32
+ checks:
+ min: 1
+ -
+ name: queues
+ doc: receive queues to bind the dmabuf to.
+ type: nest
+ nested-attributes: queue-id
+ multi-attr: true
+ -
+ name: fd
+ doc: dmabuf file descriptor to bind.
+ type: u32
+ -
+ name: id
+ doc: id of the dmabuf binding
+ type: u32
+ checks:
+ min: 1

operations:
list:
@@ -619,6 +652,20 @@ operations:
- rx-bytes
- tx-packets
- tx-bytes
+ -
+ name: bind-rx
+ doc: Bind dmabuf to netdev
+ attribute-set: dmabuf
+ flags: [ admin-perm ]
+ do:
+ request:
+ attributes:
+ - ifindex
+ - fd
+ - queues
+ reply:
+ attributes:
+ - id

mcast-groups:
list:
diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h
index 43742ac5b00da..91bf3ecc5f1d9 100644
--- a/include/uapi/linux/netdev.h
+++ b/include/uapi/linux/netdev.h
@@ -173,6 +173,16 @@ enum {
NETDEV_A_QSTATS_MAX = (__NETDEV_A_QSTATS_MAX - 1)
};

+enum {
+ NETDEV_A_DMABUF_IFINDEX = 1,
+ NETDEV_A_DMABUF_QUEUES,
+ NETDEV_A_DMABUF_FD,
+ NETDEV_A_DMABUF_ID,
+
+ __NETDEV_A_DMABUF_MAX,
+ NETDEV_A_DMABUF_MAX = (__NETDEV_A_DMABUF_MAX - 1)
+};
+
enum {
NETDEV_CMD_DEV_GET = 1,
NETDEV_CMD_DEV_ADD_NTF,
@@ -186,6 +196,7 @@ enum {
NETDEV_CMD_QUEUE_GET,
NETDEV_CMD_NAPI_GET,
NETDEV_CMD_QSTATS_GET,
+ NETDEV_CMD_BIND_RX,

__NETDEV_CMD_MAX,
NETDEV_CMD_MAX = (__NETDEV_CMD_MAX - 1)
diff --git a/net/core/netdev-genl-gen.c b/net/core/netdev-genl-gen.c
index 8350a0afa9ec7..6b7fe6035067b 100644
--- a/net/core/netdev-genl-gen.c
+++ b/net/core/netdev-genl-gen.c
@@ -27,6 +27,11 @@ const struct nla_policy netdev_page_pool_info_nl_policy[NETDEV_A_PAGE_POOL_IFIND
[NETDEV_A_PAGE_POOL_IFINDEX] = NLA_POLICY_FULL_RANGE(NLA_U32, &netdev_a_page_pool_ifindex_range),
};

+const struct nla_policy netdev_queue_id_nl_policy[NETDEV_A_QUEUE_TYPE + 1] = {
+ [NETDEV_A_QUEUE_ID] = { .type = NLA_U32, },
+ [NETDEV_A_QUEUE_TYPE] = NLA_POLICY_MAX(NLA_U32, 1),
+};
+
/* NETDEV_CMD_DEV_GET - do */
static const struct nla_policy netdev_dev_get_nl_policy[NETDEV_A_DEV_IFINDEX + 1] = {
[NETDEV_A_DEV_IFINDEX] = NLA_POLICY_MIN(NLA_U32, 1),
@@ -74,6 +79,13 @@ static const struct nla_policy netdev_qstats_get_nl_policy[NETDEV_A_QSTATS_SCOPE
[NETDEV_A_QSTATS_SCOPE] = NLA_POLICY_MASK(NLA_UINT, 0x1),
};

+/* NETDEV_CMD_BIND_RX - do */
+static const struct nla_policy netdev_bind_rx_nl_policy[NETDEV_A_DMABUF_FD + 1] = {
+ [NETDEV_A_DMABUF_IFINDEX] = NLA_POLICY_MIN(NLA_U32, 1),
+ [NETDEV_A_DMABUF_FD] = { .type = NLA_U32, },
+ [NETDEV_A_DMABUF_QUEUES] = NLA_POLICY_NESTED(netdev_queue_id_nl_policy),
+};
+
/* Ops table for netdev */
static const struct genl_split_ops netdev_nl_ops[] = {
{
@@ -151,6 +163,13 @@ static const struct genl_split_ops netdev_nl_ops[] = {
.maxattr = NETDEV_A_QSTATS_SCOPE,
.flags = GENL_CMD_CAP_DUMP,
},
+ {
+ .cmd = NETDEV_CMD_BIND_RX,
+ .doit = netdev_nl_bind_rx_doit,
+ .policy = netdev_bind_rx_nl_policy,
+ .maxattr = NETDEV_A_DMABUF_FD,
+ .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
+ },
};

static const struct genl_multicast_group netdev_nl_mcgrps[] = {
diff --git a/net/core/netdev-genl-gen.h b/net/core/netdev-genl-gen.h
index 4db40fd5b4a9e..67c34005750c3 100644
--- a/net/core/netdev-genl-gen.h
+++ b/net/core/netdev-genl-gen.h
@@ -13,6 +13,7 @@

/* Common nested types */
extern const struct nla_policy netdev_page_pool_info_nl_policy[NETDEV_A_PAGE_POOL_IFINDEX + 1];
+extern const struct nla_policy netdev_queue_id_nl_policy[NETDEV_A_QUEUE_TYPE + 1];

int netdev_nl_dev_get_doit(struct sk_buff *skb, struct genl_info *info);
int netdev_nl_dev_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb);
@@ -30,6 +31,7 @@ int netdev_nl_napi_get_doit(struct sk_buff *skb, struct genl_info *info);
int netdev_nl_napi_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb);
int netdev_nl_qstats_get_dumpit(struct sk_buff *skb,
struct netlink_callback *cb);
+int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info);

enum {
NETDEV_NLGRP_MGMT,
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 05f9515d2c05c..2d726e65211dd 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -721,6 +721,12 @@ int netdev_nl_qstats_get_dumpit(struct sk_buff *skb,
return err;
}

+/* Stub */
+int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
+{
+ return 0;
+}
+
static int netdev_genl_netdevice_event(struct notifier_block *nb,
unsigned long event, void *ptr)
{
diff --git a/tools/include/uapi/linux/netdev.h b/tools/include/uapi/linux/netdev.h
index 43742ac5b00da..91bf3ecc5f1d9 100644
--- a/tools/include/uapi/linux/netdev.h
+++ b/tools/include/uapi/linux/netdev.h
@@ -173,6 +173,16 @@ enum {
NETDEV_A_QSTATS_MAX = (__NETDEV_A_QSTATS_MAX - 1)
};

+enum {
+ NETDEV_A_DMABUF_IFINDEX = 1,
+ NETDEV_A_DMABUF_QUEUES,
+ NETDEV_A_DMABUF_FD,
+ NETDEV_A_DMABUF_ID,
+
+ __NETDEV_A_DMABUF_MAX,
+ NETDEV_A_DMABUF_MAX = (__NETDEV_A_DMABUF_MAX - 1)
+};
+
enum {
NETDEV_CMD_DEV_GET = 1,
NETDEV_CMD_DEV_ADD_NTF,
@@ -186,6 +196,7 @@ enum {
NETDEV_CMD_QUEUE_GET,
NETDEV_CMD_NAPI_GET,
NETDEV_CMD_QSTATS_GET,
+ NETDEV_CMD_BIND_RX,

__NETDEV_CMD_MAX,
NETDEV_CMD_MAX = (__NETDEV_CMD_MAX - 1)
--
2.46.0.rc1.232.g9752f9e123-goog